The proposed research will involve study of Nerve Growth Factor (NGF) content in the serum,brain, and a number of body organs of the mouse, rat, and fetal lamb at several different ages during the perinatal period of development. Our hypothesis is that there are age-related developmental relationships of NGF in these organs as well as in amniotic fluid and placental, which, when related to known biochemical and physiological parameters of development, will provide insight into the metabolic control and regulation of early nervous system development. Thus we have established a radioimmunoassay for mouse NGF in tissues, and are in the process of establishing similar RIA's for use in the rat and human species. We have purified mouse NGF from submaxillary gland, rat NGF from placenta, and human NGF from placenta. We will continue to study these normal biochemical interrelationships and will also study these hormonal and biochemical relationships under conditions of hyper- & hypothyroidism as well as hyperglucocorticoidism and undernutrition.